Testing apparatus for golf clubs



Sept. 10, 1940. w. L. WETTLAUFER TESTING APPARATUS FOR GOLF CLUBS Filed April 20,- 1958 INVENTOR Y [M g/047 ATTQRN III/II ZViZ/i'am Patented Sept. 10, 1940 UNITED STATES PATENT OFFICE 8 Claims.

This invention relates to golf clubs, and it has particular reference to a club embodying means for indicating the zone of contact, and the effective force of impact, between the club face and ball when the clubis swung by the player.

It is universally recognized that, unless a golf club is of a weight and balance best suited to the physique and form of the player, there is an increased probability of repeated errors in the '1 swing, leading to shots which are unsatisfactory.

,ers individual style, it is practically impossible for the average player to compensate for the resulting errors by modifications of his natural mode of play. A 1

The correct swing'of a golf club is, of course, directly comparable to the swing of a pendulum, and if the relation between club length and weight distribution, on the one hand, and the players form, on the' other, is not correct, then there is a constant tendency for the club head to depart laterally from the intended arc of the swing, resulting in shots which are off line. Another efiect of such deviations is to diminish the total impact between club face and ball, since the maximum impact is obtained when the club meets the ball in such manner that a plane normal to the center of the ball passes normally through the club face and the center of mass of the clubhead. This contact is usually assumed to exist when the ball is hit on the sweet spot.

of the club.

According to the present invention, a practice or test club is provided, having removable and interchangeable weights and indicators, so that the player or instructor may, by trial and experifrom thefollowing detailed description of a specific embodiment thereof, illustrated in the accompanying drawing, wherein:

Fig. 1 is an elevation of the club, looking from the face side, the shaft being fragmentarily shown;

Fig. 2 .is a top plan view of the club head, showing adjustable weights, and contact and impact indicators disposed therein; and,

Figs. 3, 4, and 5 are sections taken respectively on the lines 3-3, 4-4, and 55 of Fig. 2.

As shown in Figs. 1 and 2, the test club of the present invention comprises a hollow head I0, generally conforming to the accepted contour of woods, and having a striking face II and a hosel I 2 for the reception of a shaft [3. The shaft I3 is detachable, for replacement by a shaft of different length, flexibility, or weight, and it is also rotatably adjustable in the hosel l2. The details of such adjustment do not, however, constitute anovel element of this invention, being described-in 'my prior Patent No. 2,067,556, patented January 12, 1937.

The striking face H, in distinction to ordinary playing clubs, is formed with three apertures respectively located adjacent the toe, sweet spot, and heel of the club, which receive pins I4, I5, and I6, normally. disposed with respect to the club face, and adapted to be driven into the hollow portion of the head when impacted by a ball. As shown in Fig. 4, each pin is provided with a cotter ll at the end within the head, to prevent unintended removal from the face of the club, and with an enlarged portion 18 on the opposite end. Obviously, this specific construction may be modified by employing other means to. hold the pin within its aperture. Each aperture is also intersected by a vertically dis posed aperture l9, adapted to receive a coiled spring 2| which is held in place-by a set screw 22. The frictional drag of the lower end of the spring 2| against the pin prevents movement of the pin except under the forceof impact with a ball, or manual pressure intentionally applied in the opposite direction.

These indicator pins show the zone of the face which .contacts the ball at the time of impact; Thus, if'the player should find that impact consistently occurred on the toe, or heel, for example, he would have a positive indication as to the adjustments which should be made to bring the sweet spot of the club head in contact with the ball. If the player obtained contact at first one spot and then another, the instructor could assume that theplayer had not yet developed any particular groove for his swing, and would be guided into a closer observance of the numerous elements of form material to a correct style of play, as well as desirable modification of the club itself.

Disposed within the hollow head, and at the rear thereof, are two studs, 23 and 24, on each of which are positioned a number of weights or Washers 25, held in place by nuts 26. These studs are located on opposite sides of the plane normal to the club face which passes through the center of symmetry of the club head, and it is intended that the washers be of such Weight, for example, two or three grams, that the actual center of gravity of the club head may be shifted very slight distances from or in this plane,,by adding, removing, or interchanging the weights. Thus, analysis of the impacts obtained by practice swings may show that the club is too heavy to be controlled by the player, and then enough weights would be removed to obtain a club which the player could control. Or, analysis might show that the center of mass should be located ahead of, or behind, the plane of symmetry, to the end that the impact should be obtained on the sweet spot of the club. That is to say, the adjustment of the weights 25, made after observation of the displacement of the pins I4, IE, or

l6, leads to the determination of the total weight and distribution of weight best suited to the player.

While these means facilitate the determination of a club which the player can swing consistently, such means do not, of necessity, determine whether or not the player has developed a perfect swing, or one productive of the maximum force exerted against the ball. Accordingly, the invention includes a force or impact indicator. As herein illustrated, this device consists of a rod 28 disposed parallel to the sole of the club and within the hollow portion therof. The rod may be secured in place by abutment against a recess 29 (Fig. 3) within the face H and a bearing 3! tapped through the rear of the club, and adapted to receive a lock screw 32.

:One portion of the rod 28 is formed with ratchet teeth 33, and the rod is encircled by a slide member 34 formed with spaced upstanding ears 35 between which is pivoted a pawl 36 (see Fig. 5). The pawl is in the form of a lever having a forward downturned end 31 adapted to run over the ratchet teeth when the slide moves forward, and to resist movement in the opposite direction. The opposite end 38 of the lever may be manually depressed against the forceof a leaf spring 39, one end of which is connected to the end 38, and the other end of which bears on the body of the slide 34. To simplify the assembly, the pivot pin 4! for the pawl 36 is extended to the forward end of the rod 28, thus providing a spring portion 42 which is utilized to resist the forward movement of the slide along the rod.

It will be appreciated that, when the club is swung into contact with the ball, the reaction of the blow forces the slide 34 along the rod 28 against whatever frictional resistance there may be, and the resistance of the spring 42, which is compressed during such movement. The end 31 of the pawl lever 36 successively engages the teeth of the ratchet 33 during the motion, andv of the slide will be proportional to the impact,

this device measures the effective force with which the ball is hit. Since the rod 28 is located adjacent the plane of symmetry of the club head, the greatest displacement of the slide will take place when the most effective impact occurs. Thus, by a conjoint reading of the impact meter and the indicator pins, information may be obtained as to the effect of weight distribution, and thereby the adjustment best suited to the player.

It will therefore be understood that the club of this invention is a club intended primarily for stroke analysis, to the end that the player may determine the physical characteristics of the club best suited to him. In the process of testing with this club, information may also be gained which will reveal intrinsic defects in the players form, and which cannot readily be observed, even by skilled teachers. After the player or instructor has determined the nature of the club indicated, the maker can, with the information available, produce a matched set of clubs, based on actual determinations, rather than pure surmise.

As bearing on the practicability of the invention, it may be noted that tests were made, employ'ing professionals and first flight amateurs as the subjects. Such players have, of course, a well developed and sound swing. Proper adjustments in total weight of the club, or distribution of weight, resulted in consistent series of straight and long drives, whereas with apparently small and inconsequential misadjustments, the ball would develop a hook or fade at the end of its flight, and its total flight would be from five to fifteen per 'cent less. With less skillful players, the results were even more pronounced.

It will therefore be understood that this invention provides a club with which a player may be more readily instructed in the art of playing golf, and may be provided with clubs of such physical characteristics as to enable him to play an improved game. The precise mechanical details hereinv described are, of course, susceptible of Wide variation and modification, and therefore it is intended that all such variations, combinations, or sub-combinations as are encompassed by the following claims should be deemed to be within the scope of this invention.

I claim:

1. A golf club comprising a head having a striking face, a plurality of pins slidably mounted in and projecting from said face, said pins being spaced over the area of the face to be severally contacted by a ball when the club is swung, and means for holding the pins from movement in the'head except under forces of greater magnitude than those imparted by the momentum of the club itself when swung.

2. A golf club comprising a hollow head, a. striking face on one side of the head, said head being formed with apertures normally disposed with respect to said face, said apertures being locatedat spaced areas on the face such as the toe, heel, and sweet spot thereof, pins slidably mounted in the apertures and adapted to project slightly beyond the face, means for holding said pins from accidental removal from the head, and means for holding said pins in a predetermined position against adventitious forces.

3. A golf club comprising a hollow head, a striking face having a plurality of apertures disposed therein and normal thereto, said apertures being spaced across the face,one of said apertures being located substantially at the sweet spot of the club, pins slidably mounted in they apertures, said pins being provided with means to retain them in the club head and being of such length as to extend slightly beyond the face when pushed outwardly, and spring members mounted in said head for engagement with said pins to retain them against movement except under the influence of a determinate force.

4. A-golf club having a hollow head, a rod disposed within said head, a slide on the rod,

and means interposed between the rod and slide to releasably hold said slide in any position along said rod, said means being releasable by impact of the head with a ball to permit said slide to move along the rod and thereby indicate the force of impact.

5. A golf club having a hollow head and a striking face, a rod extending from the striking face to the rear of the head, said rod being disposed within the head, a slide mounted On the rod, spring means interposed between the slide and the interior of the head for resisting movement of the slide toward the striking face, and a ratchet and pawl connection between the rod and slide to retain the slide in the position to which it is moved under the action of impact between the face and a ball.

6. A golf club comprising a hollow head, a striking face on the head, a rod extending across the cavity of the head substantially coincident with the plane of syrmnetry thereof, a slide on the rod, spring means disposed between the slide and the rod to resist forward movement of the slide toward the striking face when the face is swung against a ball, releasable means for holding the slide after said slide moves along the rod, adjustable weights disposed within the head and on either side of the rod, whereby the center of gravity .of the head may be shifted slight distances in and with respect to the plane of symmetry, and indicating pins disposed over the face of the head to indicate the portion thereof contacting the ball when the club is swung.

"I. A golf club of the wood type adapted for instruction,'practice, and stroke analysis comp-rising a hollow head, a hosel on one side of the head, a shaft adjustably mounted in the hosel, adjustable weights mounted within the head on opposite sides of the plane of symmetry thereof, a slide member mounted in the head for movement toward the face thereof when the club is swung against a ball, and indicator pins slidably mounted in the club face to indicate the area of the face contacting the ball.

8. The combination with a test golf club having a head containing adjustable weights at several locations therein and also containing an impact register, of a striking face on the head and means on the face for indicating the contact zone as affected by the adjustment of said weights.

' WILLIAM L. WETTLAUFER. 

